| /* OsmoHLR SMS-over-GSUP routing implementation */ |
| |
| /* Author: Mychaela N. Falconia <falcon@freecalypso.org>, 2023 - however, |
| * Mother Mychaela's contributions are NOT subject to copyright. |
| * No rights reserved, all rights relinquished. |
| * |
| * Based on earlier unmerged work by Vadim Yanitskiy, 2019. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU Affero General Public License as published by |
| * the Free Software Foundation; either version 3 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU Affero General Public License for more details. |
| * |
| * You should have received a copy of the GNU Affero General Public License |
| * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include <stdint.h> |
| #include <string.h> |
| #include <errno.h> |
| |
| #include <osmocom/core/talloc.h> |
| #include <osmocom/gsm/gsup.h> |
| #include <osmocom/gsm/gsm48_ie.h> |
| #include <osmocom/gsm/protocol/gsm_04_11.h> |
| |
| #include <osmocom/hlr/hlr.h> |
| #include <osmocom/hlr/hlr_sms.h> |
| #include <osmocom/hlr/gsup_server.h> |
| #include <osmocom/hlr/gsup_router.h> |
| #include <osmocom/hlr/logging.h> |
| #include <osmocom/hlr/db.h> |
| |
| /*********************************************************************** |
| * core data structures expressing config from VTY |
| ***********************************************************************/ |
| |
| struct hlr_smsc *smsc_find(struct hlr *hlr, const char *name) |
| { |
| struct hlr_smsc *smsc; |
| |
| llist_for_each_entry(smsc, &hlr->smsc_list, list) { |
| if (!strcmp(smsc->name, name)) |
| return smsc; |
| } |
| return NULL; |
| } |
| |
| struct hlr_smsc *smsc_alloc(struct hlr *hlr, const char *name) |
| { |
| struct hlr_smsc *smsc = smsc_find(hlr, name); |
| if (smsc) |
| return NULL; |
| |
| smsc = talloc_zero(hlr, struct hlr_smsc); |
| smsc->name = talloc_strdup(smsc, name); |
| smsc->hlr = hlr; |
| llist_add_tail(&smsc->list, &hlr->smsc_list); |
| |
| return smsc; |
| } |
| |
| void smsc_del(struct hlr_smsc *smsc) |
| { |
| llist_del(&smsc->list); |
| talloc_free(smsc); |
| } |
| |
| struct hlr_smsc_route *smsc_route_find(struct hlr *hlr, const char *num_addr) |
| { |
| struct hlr_smsc_route *rt; |
| |
| llist_for_each_entry(rt, &hlr->smsc_routes, list) { |
| if (!strcmp(rt->num_addr, num_addr)) |
| return rt; |
| } |
| return NULL; |
| } |
| |
| struct hlr_smsc_route *smsc_route_alloc(struct hlr *hlr, const char *num_addr, |
| struct hlr_smsc *smsc) |
| { |
| struct hlr_smsc_route *rt; |
| |
| if (smsc_route_find(hlr, num_addr)) |
| return NULL; |
| |
| rt = talloc_zero(hlr, struct hlr_smsc_route); |
| rt->num_addr = talloc_strdup(rt, num_addr); |
| rt->smsc = smsc; |
| llist_add_tail(&rt->list, &hlr->smsc_routes); |
| |
| return rt; |
| } |
| |
| void smsc_route_del(struct hlr_smsc_route *rt) |
| { |
| llist_del(&rt->list); |
| talloc_free(rt); |
| } |
| |
| /*********************************************************************** |
| * forwarding of MO SMS to SMSCs based on SM-RP-DA |
| ***********************************************************************/ |
| |
| static const struct hlr_smsc *find_smsc_route(const char *smsc_addr) |
| { |
| const struct hlr_smsc_route *rt; |
| |
| rt = smsc_route_find(g_hlr, smsc_addr); |
| if (rt) |
| return rt->smsc; |
| return g_hlr->smsc_default; |
| } |
| |
| static void respond_with_sm_rp_cause(struct osmo_gsup_req *req, |
| uint8_t sm_rp_cause) |
| { |
| struct osmo_gsup_message rsp_msg = { }; |
| |
| rsp_msg.sm_rp_cause = &sm_rp_cause; |
| osmo_gsup_req_respond(req, &rsp_msg, true, true); |
| } |
| |
| /* Short Message from MSC/VLR towards SMSC */ |
| void forward_mo_sms(struct osmo_gsup_req *req) |
| { |
| /* The length limit on the SMSC address is 20 digits, stated |
| * indirectly in GSM 04.11 section 8.2.5.2. */ |
| uint8_t gsm48_decode_buffer[11]; |
| char smsc_addr[21]; |
| const struct hlr_smsc *smsc; |
| struct osmo_cni_peer_id dest_peer; |
| |
| /* Make sure SM-RP-DA (SMSC address) is present */ |
| if (req->gsup.sm_rp_da == NULL || !req->gsup.sm_rp_da_len) { |
| osmo_gsup_req_respond_err(req, GMM_CAUSE_INV_MAND_INFO, |
| "missing SM-RP-DA"); |
| return; |
| } |
| |
| if (req->gsup.sm_rp_da_type != OSMO_GSUP_SMS_SM_RP_ODA_SMSC_ADDR) { |
| osmo_gsup_req_respond_err(req, GMM_CAUSE_INV_MAND_INFO, |
| "SM-RP-DA type is not SMSC"); |
| return; |
| } |
| |
| /* Enforce the length constrainst on SM-RP-DA, as specified in |
| * GSM 04.11 section 8.2.5.2. Also enforce absence of ToN/NPI |
| * extension octets at the same time. */ |
| if (req->gsup.sm_rp_da_len < 2 || req->gsup.sm_rp_da_len > 11 || |
| !(req->gsup.sm_rp_da[0] & 0x80)) { |
| /* This form of bogosity originates from the MS, |
| * not from OsmoMSC or any other Osmocom network elements! */ |
| LOGP(DLSMS, LOGL_NOTICE, |
| "Rx '%s' (IMSI-%s) contains invalid SM-RP-DA from MS\n", |
| osmo_gsup_message_type_name(req->gsup.message_type), |
| req->gsup.imsi); |
| respond_with_sm_rp_cause(req, GSM411_RP_CAUSE_SEMANT_INC_MSG); |
| return; |
| } |
| |
| /* Decode SMSC address from SM-RP-DA */ |
| gsm48_decode_buffer[0] = req->gsup.sm_rp_da_len - 1; |
| memcpy(gsm48_decode_buffer + 1, req->gsup.sm_rp_da + 1, |
| req->gsup.sm_rp_da_len - 1); |
| gsm48_decode_bcd_number2(smsc_addr, sizeof(smsc_addr), |
| gsm48_decode_buffer, |
| req->gsup.sm_rp_da_len, 0); |
| |
| /* Look for a route to this SMSC */ |
| smsc = find_smsc_route(smsc_addr); |
| if (smsc == NULL) { |
| LOGP(DLSMS, LOGL_NOTICE, |
| "Failed to find a route for '%s' (IMSI-%s, SMSC-Addr-%s)\n", |
| osmo_gsup_message_type_name(req->gsup.message_type), |
| req->gsup.imsi, smsc_addr); |
| respond_with_sm_rp_cause(req, |
| GSM411_RP_CAUSE_MO_NUM_UNASSIGNED); |
| return; |
| } |
| |
| /* We got the IPA name of our SMSC - forward the message */ |
| osmo_cni_peer_id_set(&dest_peer, OSMO_CNI_PEER_ID_IPA_NAME, |
| (const uint8_t *) smsc->name, |
| strlen(smsc->name) + 1); |
| osmo_gsup_forward_to_local_peer(req->cb_data, &dest_peer, req, NULL); |
| } |
| |
| /*********************************************************************** |
| * forwarding of MT SMS from SMSCs to MSC/VLR based on IMSI |
| ***********************************************************************/ |
| |
| void forward_mt_sms(struct osmo_gsup_req *req) |
| { |
| struct hlr_subscriber subscr; |
| struct osmo_cni_peer_id dest_peer; |
| int rc; |
| |
| rc = db_subscr_get_by_imsi(g_hlr->dbc, req->gsup.imsi, &subscr); |
| if (rc < 0) { |
| osmo_gsup_req_respond_err(req, GMM_CAUSE_IMSI_UNKNOWN, |
| "IMSI unknown"); |
| return; |
| } |
| /* is this subscriber currently attached to a VLR? */ |
| if (!subscr.vlr_number[0]) { |
| osmo_gsup_req_respond_err(req, GMM_CAUSE_IMPL_DETACHED, |
| "subscriber not attached to a VLR"); |
| return; |
| } |
| osmo_cni_peer_id_set(&dest_peer, OSMO_CNI_PEER_ID_IPA_NAME, |
| (const uint8_t *) subscr.vlr_number, |
| strlen(subscr.vlr_number) + 1); |
| osmo_gsup_forward_to_local_peer(req->cb_data, &dest_peer, req, NULL); |
| } |
| |
| /*********************************************************************** |
| * READY-FOR-SM handling |
| * |
| * An MSC indicates that an MS is ready to receive messages. If one |
| * or more SMSCs have previously tried to send MT SMS to this MS and |
| * failed, we should pass this READY-FOR-SM message to them so they |
| * can resend their queued SMS right away. But which SMSC do we |
| * forward the message to? 3GPP specs call for a complicated system |
| * where the HLR remembers which SMSCs have tried and failed to deliver |
| * MT SMS, and those SMSCs then get notified - but that design is too |
| * much complexity for the current state of Osmocom. So we keep it |
| * simple: we iterate over all configured SMSCs and forward a copy |
| * of the READY-FOR-SM.req message to each. |
| * |
| * Routing of responses is another problem: the MSC that sent |
| * READY-FOR-SM.req expects only one response, and one can even argue |
| * that the operation is a "success" from the perspective of the MS |
| * irrespective of whether each given SMSC handled the notification |
| * successfully or not. Hence our approach: we always return success |
| * to the MS, and when we forward copies of READY-FOR-SM.req to SMSCs, |
| * we list the HLR as the message source - this way SMSC responses |
| * will terminate at this HLR and won't be forwarded to the MSC. |
| ***********************************************************************/ |
| |
| static void forward_req_copy_to_smsc(const struct osmo_gsup_req *req, |
| const struct hlr_smsc *smsc) |
| { |
| const char *my_ipa_name = g_hlr->gsup_unit_name.serno; |
| struct osmo_gsup_message forward = req->gsup; |
| struct osmo_ipa_name smsc_ipa_name; |
| |
| /* set the source to this HLR */ |
| forward.source_name = (const uint8_t *) my_ipa_name; |
| forward.source_name_len = strlen(my_ipa_name) + 1; |
| |
| /* send it off */ |
| LOG_GSUP_REQ(req, LOGL_INFO, "Forwarding source-reset copy to %s\n", |
| smsc->name); |
| osmo_ipa_name_set(&smsc_ipa_name, (const uint8_t *) smsc->name, |
| strlen(smsc->name) + 1); |
| osmo_gsup_enc_send_to_ipa_name(g_hlr->gs, &smsc_ipa_name, &forward); |
| } |
| |
| void rx_ready_for_sm_req(struct osmo_gsup_req *req) |
| { |
| struct hlr_smsc *smsc; |
| |
| /* fan request msg out to all SMSCs */ |
| llist_for_each_entry(smsc, &g_hlr->smsc_list, list) |
| forward_req_copy_to_smsc(req, smsc); |
| |
| /* send OK response to the MSC and the MS */ |
| osmo_gsup_req_respond_msgt(req, OSMO_GSUP_MSGT_READY_FOR_SM_RESULT, |
| true); |
| } |